J/ApJ/479/427ivo://CDS.VizieR/J/ApJ/479/427doi:10.26093/cds/vizier.14790427CDSGonzalez G.Lambert D.L.Giridhar S.1997-12-09T20:01:15Z1997-12-09T21:01:11ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frvariable-starschemical-abundanceshorizontal-branch-starsAnalyses of the photospheric compositions of the four field RV Tauri stars, EP Lyr, DY Ori, AR Pup, and R Sge, indicate that to varying degrees they have experienced fractionation processes that have preferentially depleted their atmospheres of elements with high condensation temperatures. The depletion, as indicated by, for instance, [S/Fe], is greatest for DY Ori, [S/Fe]=2.5, and least for R Sge, [S/Fe]=0.9. The initial composition, presumably indicated by the sulfur abundance, was nearly solar for AR Pup, R Sge, and DY Ori, while it was about 0.6--- less than solar for EP Lyr. This implies that the RV Tauri stars as a group may not be as metal-poor as previously thought---they are instead ``metal-depleted''. The field RV Tauri's are not halo stars, but probably belong to the thick disk. This brings to seven the number of type II Cepheids that show such a trend; the other three are IW Car and V1 in omega Cen, RV Tauri stars, and ST Pup, a W Virginis star. The 12C/13C ratios for EP Lyr and DY Ori are 9+/-1 and 6+/-3, respectively, indicating that CN-cycled material has been mixed with their surface layers. This is consistent with the general consensus that RV Tau stars are in a post-AGB evolutionary stage. There is also evidence that EP Lyr has a stellar mass companion, but additional observations are required to calculate an orbit; hence, EP Lyr could be a link to the group of metal-depleted, high-latitude A-F supergiants, all of which are binaries.1997ApJ...479..427Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/479/427CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/479/427https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/479/427http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/479/427https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/479/427https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/479/427http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/479/427GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/479/427/table3Individual abundance results for EP LyrEW3? Equivalent width, 1996 Mar 30.0001nmspect.line.eqWidthintlog(Eps3)? Abundance at lambda, 1996 Mar 3phys.abundfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonAtomic speciesphys.atmol.elementcharlog(Eps0)Solar abundance for the ionphys.abundfloatlambdaWavelength0.1nmem.wlfloatEPLow energy potentialeVphys.energy;phys.atmol.levelfloatlog(gf)log of oscillator strengthphys.atmol.wOscStrengthfloatEW1? Equivalent width, 1994 June 25-270.0001nmspect.line.eqWidthfloatlog(Eps1)? Abundance at lambda, 1994 June 25-27phys.abundfloatEW2? Equivalent width, 1995 June 10&120.0001nmspect.line.eqWidthfloatlog(Eps2)? Abundance at lambda, 1995 June 10&12phys.abundfloatJ/ApJ/479/427/table6Individual abundance results for R SgeEPLow energy potentialeVphys.energy;phys.atmol.levelfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonAtomic speciesphys.atmol.elementcharlog(Eps0)Solar abundance for the ionphys.abundfloatlambdaWavelength0.1nmem.wlfloatlog(gf)log of oscillator strengthphys.atmol.wOscStrengthfloatEW1? Equivalent width, 1992 May 220.0001nmspect.line.eqWidthintlog(Eps1)? Abundance at lambda, 1992 May 22phys.abundfloatEW2? Equivalent width, 1994 June 240.0001nmspect.line.eqWidthintlog(Eps2)? Abundance at lambda, 1994 June 24phys.abundfloatEW3? Equivalent width, 1994 July 290.0001nmspect.line.eqWidthintlog(Eps3)? Abundance at lambda, 1994 July 29phys.abundfloatEW4? Equivalent width, 1995 June 120.0001nmspect.line.eqWidthintlog(Eps4)? Abundance at lambda, 1995 June 12phys.abundfloat